WP 1: Screening of trees for saline environments and the production of relevant salinity data

See here results from the work package (link)

The objective of this work package is to select a number of tree species or varieties with good production characteristics for saline environments and to produce relevant salinity data about these species.

Crops show different reactions to salinity stress. Freshwater species (like wheat) only accept a salinity threshold close to zero and then drop productivity instantly with increasing salinity. Salt tolerant trees continue constant under increasing salinity and halophytes may increase their productivity at the lower end of the salinity spectrum. The salinity threshold represents the maximum degree of salinity at which a given plant still produces at 100%. The salinity curve indicates the measure of decline in production once the salinity threshold is passed. Salinity curves provide the information that is needed for selecting crops or varieties for certain levels of salinity and for choosing the most appropriate tree species for a specific saline environment.

For most biosaline tree species these data are still not existing or incomplete. Salt tolerance of trees is difficult to quantify because it varies considerably with many environmental factors (e.g., soil fertility, soil physical conditions, distribution of salt in the soil profile, irrigation methods, and climate) and plant factors (e.g., stage of growth, variety, and rootstock) (Ghassemi et al. 1995, Kozlowski and Pallardy 1997b in Kozlowski, 1997). Woody plants usually are relatively salt tolerant during seed germination, much more sensitive during the emergence and young seedling stages, and become progressively more tolerant with increasing age through the reproductive stage (Shannon et al. 1994).